Studies of the interaction between metalloporphyrin films and phenols in a preconcentration type sensor

摘要

Metalloporphyrins have been used as sensors to detect phenols. We describe several experiments that indicate that the increment of current response is due to a preconcentration effect of the phenolic analyte in the modifying layer. The aromatic structure seems to be crucial to achieve this goal, indicating pi-pi interaction. The electrical response to phenols of a variety of poly[M-(PPIX)I films, M = Ni-II, Co-II and Cu-II was measured suggesting an axial ligand-metalloporphyrin interaction. The IR spectras of p-nitrophenol with and without porphyrins were obtained showing a gradual decrease of the signal at 1205.6 cm(-1), corresponding to C-O stretching acid the presence of two new peaks (1236.7, 1167.4cm(-1)). Further signal at 1345 cm(-1) corresponding to symmetric (ArNO2) N-O stretching, remains unchanged. Therefore, these results indicate that the -C-OH the OH group is involved in the binding. [References: 23]